As is known, PLCs have found widespread applicability in a number of technological arts including communications and biomedical instrumentation—among others. In a number of such applications, controlling light that propagates through the PLC (i.e., transmissivity/reflectivity of the PLC) is of critical importance. Given this importance, systems, methods structures that provide or otherwise facilitate control of the transmissivity/reflectivity of a PLC would represent a welcome addition to the art.